Portable electronic devices are popular tools for both business and personal activities. The smallest and lightest of these devices are suitable for and most often carried and operated while being held in the hand of its user. Typical handheld electronic devices include cellular phones, personal digital assistants, cameras, as well as medical devices such as analyte measurement devices.
A typical handheld electronic device usually includes a circuit board and user display. Both the circuit board and display are assembled into or otherwise integrated with a housing. In order to allow the circuit board and display to be easily positioned inside the housing, conventionally, the housing is divided into an upper housing and a lower housing. The display is typically supported by the upper housing and the circuit board is usually supported by the lower housing although various other configurations are utilized. The upper and lower housing are assembled to form the housing and because of this structure, there is a mating seam between the upper and lower housing.
In handheld devices, especially those with plastic cases, electrostatic discharge is a particular concern. To avoid such disruptions, many devices contain some form of electrostatic discharge protection. Handling the device, sliding it along a table, or simply picking it up for use can generate electrostatic voltages of 25 kilovolts or more. While each discharge is extremely short in duration, such high voltages can cause disruptions to electronic devices such as loss of memory, device reset, or even physical damage that results in fusing or rupture of device components. Even though the case itself generally has a high electrical strength, there are leakage zones particularly along housing seams or where a lid or cover that provides access to internal electronics is fitted onto the main housing. Electrostatic discharge can disrupt or damage a handheld electronic device when a user touches or handles the device in a way that causes a spark to traverses from the user at or near an opening in the handheld device such as at a seam in the housing or the like. When a spark occurs at or near such an opening the spark can pass through the opening and reach an electronic component such as a circuit board or the like. Accordingly, care must be taken to prevent electrostatic discharge from reaching and damaging, interrupting, or otherwise affecting sensitive electronic components.